FIG. 1 depicts a schematic diagram of a telecommunications system in the prior art, which comprises: central office 102, remote terminal equipment 101, digital carrier loop 105, wireline terminals 108-1 through 108-m, which are connected to central office 102 via customer subscriber lines 109-1 through 109-m, respectively, and wireline terminals 110-1 through 110-n, which are connected to remote terminal equipment 101 via customer subscriber lines 111-1 through 111-n.
Central office 102 provides nominal telecommunications service to customer subscriber lines 109-1 through 109-m, in well-known fashion, and nominal telecommunications service to customer subscriber lines 111-1 through 111-n via remote terminal equipment 101 and digital carrier loop 105.
Typically, remote terminal equipment is used when the distance between a central office and a wireline terminal is too great (e.g., more than a few kilometers, etc.). In such cases, remote terminal equipment is placed geographically near to the wireline terminals and a multiplexed digital carrier loop carries multiple simultaneous calls between the central office and the remote terminal equipment. In this circumstance, the remote terminal equipment functions as a concentrator.
When digital carrier loop 105 experiences a failure (e.g., its cable was accidentally cut by ditch digging equipment, etc.), telecommunications service to all of wireline terminals 110-1 through 110-n is unavailable. Although gaps in telecommunications service can be rare, even a rare gap can be catastrophic when emergency situations arise. Therefore, the need exists for a technique for providing backup telecommunications service to customer subscriber lines serviced by remote terminal equipment.